Mohammad Alqahtani, researcher of the Multifunctional Materials Lab, is conducting research to develop a new manufacturing method and testing protocol for the fabrication of biocompatible catalyst-carrier for controlled drug delivery. The carrier could be used as a prodrug activation agent when implanted in cancerous tissues in the human body. When orally-ingested drugs are deployed into the area under treatment through the blood stream, the catalyst could activate the prodrugs and these affect the area by releasing anticancer treatment. In this research, a titanium-based carrier was used to manufacture the medical device due to their biocompatibility and non cytotoxicity.

In a feasibility study, the samples were made as porous carriers. Porous materials have larger surface area than solid materials. Therefore, when the contact area between the drug and the carrier increases this has a potency effect on the effectiveness of the drug.

His work has been presented recently

This work is a continuation of the research work already presented here and published here and here.

We have published our most recent results on how porosity and pore size affect both mechanical properties and biological response of osteoblastic cells on titanium porous structures.

Working with volumetric porosities that match those of cortical and trabecular bone, we finely controlled the pore size in the substrate with the aim to assess how a variation in pore size can tailor mechanical properties (i.e. stiffness and strength). Furthermore, we report how we could establish regressions that would allow us to create a design tool based on porosity, so it would return the desired mechanical properties values.

From a bioengineering viewpoint, the results from this study showed that scaffolds with the lowest pore range (45-106um) presented the largest number of cells attached in the early days (day 1 and 3) indicating this microarchitecture was the best indicated for cell attachment. Pore range >300 mm exhibited the most favourable conditions for cell proliferation, surpassing those on the control samples. The viability of scaffolds with pore size 212-300um was the poorest, indicating these scaffolds do not promote cell proliferation for osteosarcoma osteoblasts due to the distance the cells had to span.

Proliferation data from the osteoblasts on titanium porous (A,B 1-4) and non-porous (Ti) normalised to the previous timepoint of culture (in/in-1, n=3, 7, 12); as it appears in https://www.ncbi.nlm.nih.gov/pubmed/28532024

We have published the results arising from our studies on open cell polymeric foams that can be tailored so that they support those who are bed bound or wheelchair users providing them with general well being and alleviating pressure points.

Avoiding pressure points, managing sores and permitting air permeability are the three main design specifications that clinicians aim to when choosing a cushion. In addition to that, a functional cushion, such as those who support lateral movements (e.g. leaning sideways to grab a glass of water and be helped to return to your initial position without compromising one’s stability) and protect from vibration and impacts (e.g. dropping off a curb), are the focus of our research project.

The Multifunctional Materials Lab and clinicians from the NHS have studied how we can help their clinician colleagues understand cushion performance and therefore aid them with the prescription of these to patients and users.

The International Standard that regulates developments in this topic is the ISO16840-2:2007, which is currently under revision. We are hoping our work to inform their work and assist in their revisions for the replacement ISO 16840-2.

Our most recent results on the importance of tailoring porosity engineered materials for cell regeneration are to be published in the Journal of Alloys and Compounds.

Porous scaffolds manufactured via powder metallurgy and sintering were designed for their structure (i.e. pore size and porosity) and mechanical properties (stiffness, strength) to be controlled and tailored to mimic those of human bone. The scaffolds were realised to fulfill three main objectives:

(i) to obtain values of stiffness and strength similar to those of trabecular (or spongy) bone, with a view of exploiting these as bone grafts that permit cell regeneration,

(ii) to establish a relationship between stiffness, strength and density that allows tailoring for mass customisation to suit patient’s needs; and

The results obtained using a very low stiffness alloy (Ti35Nb4Sn) further lowered with the introduction of nominal porosity (30–70%) with pores in the ranges 180–300 μm and 300–500 μm showed compatibility for anatomical locations typically subjected to implantation and bone grafting (femoral head and proximal tibia). The regression fitting parameters for the linear and power law regressions were similar to those found for bone specimens, confirming a structure favourable to capillary network formation. Biological tests confirmed non-cytotoxicity of the alloy.

Scaffolds of porosity nominal 50%vol and pore range 300–500 μm performed best in the adhesion and propagation assays due to a good balance between surface area and pore cavity volume.

The Multifunctional Materials Lab has recently published our results on porosity tailored titanium scaffolds. The results were very interesting and demonstrated there is more to what the eye can see in a first pass: cells are extremely sensitive to cavities and ‘think’ about whether they should bridge a gap or simply fill the hole.

The effect of pore size and porosity on elastic modulus, strength, cell attachment and cell proliferation was studied for Ti porous scaffolds manufactured via powder metallurgy and sintering. Porous scaffolds were prepared in two ranges of porosities so that their mechanical properties could mimic those of cortical and trabecular bone respectively. Space-holder engineered pore size distributions were carefully determined to study the impact that small changes in pore size may have on mechanical and biological behaviour. The Young’s moduli and compressive strengths were correlated with the relative porosity. Linear, power and exponential regressions were studied to confirm the predictability in the characterisation of the manufactured scaffolds and therefore establish them as a design tool for customisation of devices to suit patients’ needs. The correlations were stronger for the linear and the power law regressions and poor for the exponential regressions. The optimal pore microarchitecture (i.e. pore size and porosity) for scaffolds to be used in bone grafting for cortical bone was set to < 212 μm with volumetric porosity values of 27–37%, and for trabecular tissues to 300–500 μm with volumetric porosity values of 54–58%. The pore size range 212–300 μm with volumetric porosity values of 38–56% was reported as the least favourable to cell proliferation in the longitudinal study of 12 days of incubation.

Have you ever seen the seat testing device at IKEA? We have used a very similar one in our study.

IKEA durability test

Open cell polymeric foams can be tailored so that the support provided and the level of stability is customised to people’s needs. For those who are bed bound or wheelchair users the selection of a cushion can improve their health and general well being. Avoiding pressure points, managing sores and permitting air permeability are the three main design specifications that patients and clinicians aim to when choosing a cushion. In addition to that, a functional cushion, such as those who support lateral movements (e.g. leaning sideways to grab a glass of water and be helped to return to your initial position without compromising one’s stability) and protect from vibration and impacts (e.g. dropping off a curb), are the focus of our last research project.

My team and I have had the privilege to work with the biomechanics and physiotherapists at the SMART Centre at Astley Ainslie Hospital in Edinburgh to study how we can help their clinician colleagues understand cushion performance and therefore aid them with the prescription of these to patients and users.

The results from our study have been presented at the PMG 2012 Conference and recently published by the Assistive Technology journal (free e-prints can be collected here). This has allowed us to interact with the community that is preparing the new version of the ISO16840-2:2007 which will regulate developments in this area.

The medical device we designed to help midwives monitor labour with minimum interruption has seen the light! Different newspapers and media have been attracted to our invention, a team effort from our colleagues in Univ of Edinburgh and NHS, Heriot-Watt University, and us in Loughborough.

This has been a great enterprising opportunity for us. Being able to form a team with engineers, designers, medics and business developers has been truly rewarding. We all showed great enthusiasm and reached out to understand each others’ ‘language’ so we could bring the project to a fruitful completion. Working with midwives for the development of a new medical device was great because they were able to provide us with insightful input during the design stages, and with useful feedback in the development phase. We hope the device will help the midwives carry out their work in more comfortable conditions, and for future mothers-to-be to benefit from this device that allows them to experience a more dignifying labour.

The work has been presented at the Perinatal Medicine 2014 (Harrogate International Centre, Monday 9th – Wednesday 11th June 2014).

The work done by my colleague Dr Asier Unciti-Broceta and our ‘dream team’ has been published in Nature Communications.

Asier proudly presents to the world the work done using his clever “bioorthogonal” method for activating a prodrug by palladium catalyzed dealkylation. What motivates us is to move towards the eradication of the side effects of chemotheraphy (e.g. depleted immune system, hair loss, tiredness, etc) in the very near future. This is done by focusing the cancer treatment only to the affected area. Like a ‘trojan horse’, in our vision we implant the engineered catalyst carrier first. Then, by a selective activation via oral drugs, we produce the chemo-destructive effect with maximum effect on the targeted area, and minimal negative effects (i.e. death) on healthy tissue.

Standardisation is that useful process that allows us engineers to share a common ‘plane of reference’ on which to base our conversations. It is useful to know that a material (say, a slab of titanium) has the same mechanical properties when it is measured in Loughborough, Sydney, Lima or Granada.

But sometimes standardisation goes too far on the other extreme. The over-translation from observation to technical definitions might turn an ISO norm into a document that is no longer useful for practical purposes. This is particularly risky when ISO norms attempt to tabulate and measure in ‘softer’ areas such as healthcare and rehabilitation.

In a piece of work recently published here, my colleagues from the NHS Scotland SMART Centre and we have restated some practical insight to an ISO norm that guides the characterisation of wheelchair cushions for a better guidance to prescription by clinicians.

Our work has been well received by the practising community and we look forward to continue working with them.